Before I begin, this mod was done because I felt I needed more/softer padding in my seat. Due to my lack of padding “back there”, the seat is just plain too hard for me. If you don’t want softer you should consider not trying this, or adjust what kind of material you put back in to get the results you want/need.

THIS PROCEDURE HAS NOT BEEN APPROVED BY HONDA.

I saw some very similar seat mod write ups online, and wish to publicly thank those posters for inspiring me. However, I’ve yet to see a “start-to-finish” one for a heated seat model. This is my attempt.
This modification was completed start to finish in less than one day, not including getting the supplies. I am a fairly accomplished shade-tree mechanic and at no time did I feel that I was in over my head. I would say if you’re doing your own service and a big piece of the maintenance on your own bike, you are good enough to try this. But only you know for sure. I make no claim as to whether or not something can go wrong. Be your own judge of talent.
The biggest fear I had was not knowing the particulars of the heaters, and the possibility of totally messing them up before I knew it. I soon found out that if I took my time with them, it would be OK. I estimate the total job time to be 8-9 hrs, give or take. My total dollar figure was less than $25, the vast majority of that being the adhesive. Even if I’d have had to buy my replacement foam, it would have been under $50. Not bad at all, considering the good results.

And yes, my heated seats still work like they should.

The first thing to do is get the seat cover off. It’s as simple as removing the staples around the underside edge, and unhooking those pesky string loops from their keepers. The first picture shows the location of some of the keepers. There are 21 of them on my ’08 model.

To get the keepers unhooked do this:
( 1 ) Hook and pull slack in the loop. I used a generic dental pick to first get hold of the rope, then grabbed it with this coat hanger hook.

( 2 ) Use a small flat screwdriver or similar tool to pry one end of the keeper out. It snaps out sort of like a miniature version of the CD/CB radio lid in the trunk. Pry it as far up as you can without tearing it up.

( 3 ) From the side, pry some more to completely dislodge that end. You should be able to then get the other end free in the same manner.

( 4 ) This is what the keepers look like after removal. The string loop rests in the recess in the middle of the keeper (when everything is together)

Time to flip the seat over and get started. Here’s the seat minus the cover. The entire seat (except for the butt part of the driver’s seat) had this saran wrap-looking covering glued to it. I just peeled it off the best I could, and re-stuck it during final assembly. You will notice this wrap pushed back out of the way on later photos.

And these next 3 shots show where the heating elements are and some info about where the related wiring goes down through the seat.
Driver seating area

Driver backrest area

Passenger seating area

Here, I’ve peeled the heat elements from the seat foam. BE CAREFUL. Go slowly and try to keep the wire attached to its foam backing. Work the center and wing sections together so as not to stretch anything.
First the driver seat

And this one

And now a couple shots of the passenger area.

I opted to cut the wing foam on the side of the passenger seat to make it easier to glue down later. This was just personal preference. You can do or not do it. If you cut it, be careful to go far enough forward so you don’t damage the heating elements. See next pic.

Next, it’s time to do some cutting. I used a Stanley-type utility knife to take a slab from each sitting area. A new blade is mandatory. Take this part slowly also. I started in one corner, and worked my way across the seat. The technique I used was more of a “pull the loose foam up” and lightly slide the knife across the cut. Once I had enough room, it helped me to lay the knife housing flat on the cut foam. It kept the blade more horizontal and seemed to gouge it less when doing it that way. Keep checking your loose material for thickness as you go, and adjust accordingly. I used the existing indentions in the factory foam as the outline for my cutout. You want to cut out one full piece here. The cutout makes a perfect pattern for the new foam later on. Here are some shots of the process.

And again, the passenger area

After removing material, it’s time to smooth it so the new foam will lay flat and the glue will stick. You want to take this part slowly, also. Remember, you're only doing foam, not wood! I used a drill motor with a disc from the kit in next photo. The one that worked best for me was the red one that's facing up. I believe I got the kit from Auto Zone. I tried using an aggressive sanding disc on a 4” angle grinder, but it was too hard to control.
Use a dust mask, as this process throws a lot of material into the air.

And this is how the seating areas looked after sanding. Hint: get it as smooth as you can. These are ready to rebuild.

And passenger area

I used the cutout pieces of foam as patterns for the new foam and cut mine with a scissors, shaping the edges as I went. I got my foam from a local upholstery shop—cost: nothing, he gave me a couple scraps. On the driver’s seat I used two one inch thick pieces, and just one piece on the passenger area. The material is nothing magical, just plain old cushion foam. While shopping for it, I saw some at a nearby fabric supply store. At that store, enough for the job would have cost me around $20. Again, nothing fancy. Before gluing up I laid everything where it goes, draped the cover back over the seat, and sat the seat on the bike to try out the feel of it. So far, so good. On to the assembly phase. I used a 3M spray adhesive especially made for bonding foam, as shown in the photo below. The glue was purchased at the fabric supply store—cost: $15

These pics are of the seat with my new foam parts glued in, and then with the heating elements also glued back in.
Driver's seat

Driver with heaters glued back in

Passenger seat

Passenger with heaters glued on. Notice the wireway for the heating elements on the back of the passenger seat (lower-left portion of photo)

After letting the glue set up according to the directions on the can, It was put it back together time. I found it was easier to put the seat cover back on starting with the factory driver’s lumbar first. I made six or eight wire hooks out of some tie wire. Mine were 12” or so long, with a near 180 degree bend at the end. I bent them the rest of the way shut after hooking the string loop. This kept the wire hooks from snagging anything while pulling the string through the seat pad. A helper would be beneficial during the first part of this step, as a third hand would have come in very handy. The first two loops I put in are shown in the following picture (Red circles). They are the ones that tuck the cover nice and tight in the crack between the lumbar and the driver’s seat pad. They pull almost horizontally through the seat pan, and were by far the most difficult ones to get re-fastened on the bottom. The keeper-to-loop assembly is basically the reverse of removal. From this center point, I just worked my way out in both directions until all loops were secure. I pre-threaded two or three loops that were close together, and then secured those before moving on. The green circles in the picture indicate locations of some of the other keepers.

All that’s left now is stapling the cover back down. I used a T-50 Arrow brand stapler driving ¼” long staples. I started with 3/8”, but that is too long in the nose area of the seat. (Don’t ask me how I know) The factory staples appear to be 1/4”. For the most part, the Arrow did OK. I had to finish off a number of the staples with a hammer/punch, but it definitely put them in far enough to hold them until I had them all in. If you have a pneumatic power stapler, by all means use it, but the T-50 got me through. I used a similar approach with the stapler that I used with the string loops, starting in the middle and working my way up each side and toward the ends. In other words, I’d put a couple on the left, a couple on the right, in a back and forth manner. I went forward first, then to the back, but I don’t think it would have mattered which direction went first. On my seat, it was easy enough to see where the factory staples were set, so I just used those to guide me in keeping the cover stretched and in position. I did not however, use any of the same exact holes, as I figured that might weaken the cover or wallow the plastic of the pan. I don’t have a picture of this step, but the end result looks very similar to what it looked like before I started the job. It laid down well, with minimal bunching/wrinkling.

And here is the final result. In the first photo, I tried to capture the two slight wrinkles that I couldn’t get out—one on each side at the back corners of the driver’s seat pad. The other two shots show the rise in the seating areas of the driver and passenger seat, respectively. Again, I don’t have specific photos of these areas before the job, but the seat was basically flat across the middle of both seating areas.

Many thanks for a very good write up and the pictures are excellent. Looking to take mine apart this winter just to make some minor changes in the foam around the edge of the driver's seat, and this definitely will help. I've looked at many articles and videos on modifying MC seats, but our seats, especially being heated are a different animal. Now I can go into it having a good idea on what I will be encountering. Thanks again.